How is power in an electrical system expressed?

Power in an electrical system is expressed in watts or kilowatts. Watts are the standard unit of power in the International System of Units (SI) and indicate the rate at which electrical energy is consumed or produced. Kilowatts, being a multiple of watts, are often used for larger amounts of power, especially in utility billing and electrical applications where higher power levels are involved.

Understanding power is crucial because it combines both voltage (the electrical potential) and current (the flow of electricity), following the equation P = VI, where P is power in watts, V is voltage in volts, and I is current in amps. This relationship illustrates how power represents the effective use of electrical energy in a circuit.

The other units mentioned—ohms, volts, and amps—are related but measure different electrical properties: ohms measure resistance, volts measure electrical potential, and amps measure current flow. Each of these plays an important role in an electrical system, but power specifically denotes the rate of energy transfer, and that's why watts or kilowatts are the correct expressions for power.